1. Field of the Invention
This invention relates to a drive positioning apparatus used for driving a seat and/or steering wheel of, for example, an automotive vehicle back and forth, up and down, and so on, and for positioning them automatically in memorized positions suitable for a driver or drivers.
2. Description of the Prior Art
Heretofore, there has been used a drive positioning apparatus as shown in FIG. 5 and FIG. 6, for example.
Namely, the drive positioning apparatus 100 is provided with a lift-motor for driving the seat up or down, a recliner-motor for adjusting a reclining angle of a seat back of the seat and the like in addition to a slide-motor 101 for sliding the seat in a front or rear direction, however the slide-motor 101 is only shown in FIG. 5 on behalf of the aforementioned motors since they have the same circuit configuration as that of the slide-motor 101.
A power terminal 101a of the slide-motor 101 is connected with a travelling contact rl1-1 of a relay RL1, and a normal-close side fixed contact rl1-2 of the relay RL1 is connected with a power source 50 and a relay coil rl1-3 of the relay RL1 through a node a.
The relay coil rl1-3 is connected to the collector of a transistor Tr1, a manual switch port 102a of a controller 102 and a front-slide manual switch 103, and a normal-open side fixed contact rl1-4 of the relay RL1 is grounded.
The emitter of the transistor Tr1 is grounded, and the base of the transistor Tr1 is connected to an output port 102b of the controller 102.
Another power terminal 101b of the slide-motor 101 is connected with a travelling contact rl2-1 of a relay RL2, and a normal-close side fixed contact rl2-2 of the relay RL2 is connected with a relay coil rl2-3 of the relay RL2 through a node b connected to the node a.
The relay coil rl2-3 is connected to the collector of a transistor Tr2, a manual switch port 102c of a controller 102 and a rear-slide manual switch 104, and a normal-open side fixed contact rl2-4 of the relay RL2 is grounded.
The emitter of the transistor Tr2 is grounded, and the base of the transistor Tr2 is connected to an output port 102d of the controller 102.
The controller 102 is provided with a microcomputer in which signals are input from a switch board (not shown) through an I/O interface circuit, and ports 102e, 102f and 102g connected with a key switch 105 for detecting insertion and extraction of an ignition key (not shown), an accessory switch 106 for supplying electric power to respective electrical equipment including this drive positioning apparatus and an ignition switch 107 for supplying electric power to a spark plug of an engine, respectively.
The ignition switch 107 is equipped with a start switch 109 for actuating a starter motor 108 in order to start the engine, and the accessory switch 106 is so structured as to be changed into its OFF-state while the start switch 109 is in its ON-state interlockingly in order to make easy to start the engine by cutting off the power supply to the electrical equipment inclusive of the slide-motor 101 and other motors of this drive positioning apparatus and thereby lightening load of the battery (power source 50).
In a case of shifting the position of the seat into a position suitable for the driver by a hand operation, the front slide manual switch 103 or the rear-slide manual switch 104 disposed on the switch board is switched on, thereby changing the travelling contact rl1-1 of the relay RL1 into the normal open side fixed contact rl1-4 from the normal-close side fixed contact rl1-2, or the travelling contact rl2-1 of the relay RL2 into the normal open side fixed contact rl2-4 from the normal-closed side fixed contact rl2-2. Consequently, an electric current flows to the power terminal 101a from the power terminal 101b of the slide-motor 101, or flows to the power terminal 101b from the power terminal 101a of the slide-motor 101, and the slide-motor 101 rotates in the forward or reverse direction during the operation of the front-slide manual switch 103 or the rear-slide manual switch 104, so that the seat is driven in the front or rear direction slidingly.
In a case of memorizing the seat position suitable for the driver, the front-slide manual switch 103 or the rear-side manual switch 104 is changed on, thereby rotating the slide-motor 101 in the forward or reverse direction and driving the seat into the suitable position for the driver, and then the slide-motor 101 is stopped by changing off the manual switch 103 or 104. A set switch on the switch board is operated preparatively.
Subsequently, by a setting operation of a memory switch disposed on the switch board in this state, the microcomputer detects the positional displacement of the seat by counting the number of rotations (pulses) of the slide-motor 101 until the seat arrives at the present position, and the present seat position is stored in the microcomputer as the number of the rotations of the slide motor 101.
After this, it is possible to drive the slide-motor 101 automatically until the seat arrives to the suitable seat position memorized in the microcomputer according to a signal output from the output port 102b or 102d of the microcomputer by only a positioning operation of the memory switch on the switch board.
When the start switch 109 is turned on at time E in order to start the engine while the slide motor 101 is being actuated automatically in response to the positioning operation as shown in FIG. 6A, the accessory switch 106 is designed so as to be changed interlockingly into the OFF-state for a time as long as the amount of time the start switch 109 is continued to be turned on, and the automatic actuation of the slide-motor 101 is suspended temporarily in order to lighten the load of the battery and make easy to start the engine. When the start switch 109 is turned off at time F and the accessory switch 106 returns to the ON-state interlockingly, the automatic actuation of the slide-motor 101 is resumed.
However, in the aforementioned conventional drive positioning apparatus 100, when the accessory switch 106 becomes impossible to return into the ON-state by some failure, such as a contact fault, the slide-motor 101 is kept in the state in which its automatic actuation is suspended in spite of turning off the start switch 109 at time F after turning on it at time E as shown in FIG. 6B. Accordingly, there is a problem in that the seat begins unexpectedly to move toward the memorized seat position if the accessory switch 106 returns to its ON-state at time G by some reason, such as vibration from the engine.